Air bleed nozzle



Jan. 10, 1967 D. H. THORBURN AIR BLEED NOZZLE Filed Oct. 25, 1963 am,@im f 3,297,644? Patented Jan, lli), ld?

3,297,944 AIR BLEED NZZLE David H. Thorburn, Gah Park, lll., assigner toThe Powers Regulator Company, Skokie, ill., a corporation of IllinoisFiled st. 25, 1963, Ser. No. 3i8,973 6 Claims. (Cl. 137-82) Thisinvention relates to a flapper nozzle arrangement and specifically to animproved dapper nozzle in which the valving characteristic of theilapper remains essentially the same regardless of its position relativeto the nozzle.

Flapper nozzles have been extensively used in pneumatic control systemsfor regulating variables such as temperature, pressure and the like. Thedapper nozzle has many advantages famong which are its simplicity andreliability. One of the problems of the ordinary flapper nozzlearrangement is that when the ilapper moves, the angle of the valvingsurface presented by the flapper changes with respect to the axis of thenozzle. For example, if the valving surface is at right angles to theaxis of the nozzle when the `dapper is in its equilibrium position, thenat all other positions of the dapper the angularity will be somethingother than 90. This change in angularity is a result of the fact thatthe flapper is generally pivoted at one end or else is 'a cantileversupported at one end.

The change in angularity means that the valving characteristics of thevalve surface will be changed so that the relationship between thedistance of the dapper from the nozzle 'and the rate of exhausttherefrom is nonlinear. The change in character is particularlyundesirable when the force exerted on the flapper by the exhaust fromthe nozzle is to be utilized as a source of negative feedback indicatingthat the system has made an appropriate correction of a senseddeviation.

A foremost feature and object of the invention resides in the provisionof a dapper nozzle arrangement in which the valving characteristics ofthe valve remains essentially linear throughout the full range of travelof the fiapper.

A further feature and object of the invention resides in the provisionof a flapper nozzle arrangement in which the valving surface supportedby the iiapper has essentially the same attitude with respect to thenozzle regardless of the position of the ilapper.

A further feature and object of the invention resides in the provisionof a apper nozzle in which the valving surface comprises a sphericalmember mounted so as to remain essentially concentric with the nozzlethroughout the full range of travel of the dapper.

A further feature and object of the invention resides in the provisionof a tlapper nozzle arrangement which permits the use of the forceexerted on the valve supported by the apper and generated by the exhaustfrom the nozzle as a source of negative feedback indicating that thesystem has made a correction of the sensed deviation in the controlledvariable.

The aforegoing features and objects of the invention will be apparentupon reading of the speciiication with reference to the followingdrawings.

In the drawings:

FIGURE l is a sectional view illustrating the improved flapper nozzle incombination with a pneumatic control means for a heating system; and

FIGURE 2 is a cross-sectional view along the lines 2-2 of FIGURE 1.

Referring now to FIGURE l there is shown the subject invention asutilized for controlling a heating system in 'accordance with thetemperature of the yambient atmosphere. The heating system itself formsno part of the invention and serves principally to illustrate the same.It will be understood that the heating system is merely by way ofexample and that the invention may be utilized generally wherever dappernozzles are used.

The heating system includes a supply pipe 10 through which a source ofheat such as hot water ows from a suitable source such as a boiler (notshown) to heat exchanger such as a radiator (not shown). In the supplyline l() is a valve 1l which is controlled by means of the motormechanism l2. The motor mechanism may be of any conventionalconstruction such as `a spring biased diaphragm which is adapted to beforced downwardly against the force of the spring by means of airpressure. As the pressure is increased the diaphragm is forced down soas to close the valve l1. Conversely, as the pressure is decreased thediaphragm is forced upwardly by a spring so as to open the valve. Thesupply of pressure is transmitted through the conduit 13 which extendsfrom the relay valve i4. The relay 14 may be of the type adapted togenerate a pressure signal in response to a pneumatic signal receivedfrom the temperature sensing mechanism. The relay 14 is connected to thesource of supply pressure by means of the branch conduit i5 which inturn communicates with the conduit 17 leading to a source of supplypressure (not shown).

The supply pressure communicates with the nozzle assembly 28 whichsubstantially continually exhausts air to atmosphere. The exhaust airmust pass through the orice assembly 18 including the restrictor plate24 which is mounted within the fittings 19. The orifice plate includesthe orice 25 which is of a relatively small size so as to cause asubstantial reduction in pressure as the air passes therethrough. Onecommonly used orifice size is .006 inch in diameter.

The nozzle assembly 28 comprises an annular member 29 having the exhaustport 3i). The nozzle assembly 28 may be connected in any suitable mannerto the restrictor assembly ld, such las by the conduit 32.

A apper valve assembly 34 cooperates with the exhaust port 30 so as tocontrol the rate of exhaust. The flapper valve assembly comprises alever 35 which is designed to move toward and away from the port 3@ inaccordance with variations in temperature. For example as thetemperature increases, the lever 35 is adapted to move toward the port30 and conversely as the temperature decreases, the lever 35 moves away.The lever may be mounted in any suitable manner such as being pivoted atone end as indicated by the numeral`36. The movement of the lever 35 maybe effected by any suitable temperature sensitive means such as aBourdon tube, bellows, or bi-rnetallic element. In fact the lever 35 maybe constructed from a temperature sensitive bimetallic element which isfixed at one end and adapted to deflect downwardly toward the nozzle 23upon sensing an increase in temperature and away from the nozzle onsensing a decrease in temperature,

As the lever 35 moves toward the nozzle 28 the rate of exhaust isdecreased. This causes an increase in pressure on the downstream side ofthe orice plate 24. In fact, if the port 30 were completely shut off thepressure on the downstream side would ultimately equal that on theupstream side. The increase in pressure is transmitted through theconduit 22 to the relay 14. When the pressure increase is of apre-determined magnitude, the relay i4 will generate a signal ofincreased pressure which is communicated through the conduit 13 to themotor valve 12. Thus the motor valve will throttle the iiow of hot waterthrough the conduit 1d in an attempt to make a correction for theincrease in temperature sensed by the sensing element.

Conversely, if the lever 35 should be moved away from the nozzle 22% therate of exhaust will be increased. This will cause the pressure on thedownstream side of the orice 24 to decrease. The decrease in pressurewill be transmitted through the conduit 22 to the relay 14. The relay 14on sensing a decrease of a pre-determined magnitude will cause adecrease in the pressure sensed by the motor valve 12 so as to furtheropen the valve il in the line l0. This in turn will cause an increase inthe ow of hot water so as to correct for the decrease in temperature.

As mentioned previously, one of the problems of the ordinary flappernozzle arrangement is that when the ilapper moves, the angle of thevalving surface with respect to the nozzle changes. For example, it theValving surface is at right angles to the axis of the nozzle when theflapper is in its equilibrium position, then in all other positions ofthe flapper the angularity will be something other than 90. This changein angularity is a result of the fact that the apper is pivoted at oneend.

The change in angularity means that the valving characteristics of thesurface will be changed so that the relationship between the ldistanceof the fapper from the nozzle and the rate of exhaust is non-linear. Thechange in characteristic is particularly undesirable where the forceexerted on the llapper by exhaust is to be utilized as a source ofnegative feedback indicating that the system has made an appropriatecorrection of a sensed deviation.

The subject invention specifically eliminates the disad- Vantages of theordinary apper nozzle system and includes a valve member 38 which isadapted to cooperate with the 'port 30 for controlling the rate ofexhaust therefrom. In its preferred form the valve 38 is a sphere whichis connected by means of the stern 39 to a second sphere 40. The stem 39extends through an aperture 4l in the lever 35. The sphere 40 rests onthe aperture 41 and may be freely rotated about its axes. The onlylimitation on the rotations of the sphere 40 is the size of the aperture41 which serves to conne the stern 39.

The sphere 40 is maintained in its seating engagement by means of thespring member 42 which is secured to thelever 35 by means of the rivet33. The spring mem- -ber 42 -biases the sphere 4@ downwardly intoengagement with the aperture 41. The force exerted by the spring member42 may be controlled by the adjusting screw 43. In the preferred formthe force exerted by the spring 42 will be barely enough to maintain thesphere 40 in seating engagement but not to interfere with rotarymovement of the same.

As a result of this arrangement the valve member 38 may be freelyswivelled in order to maintain an exact alignment with the port 30regardless of the position of the lever 35. As the free end of the lever35 moves upwardly the valve member 33 and the stem 39 may be lswivelledin a counterclockwise direction relative to the lever so as to maintaintheir alignment with the port 30. Conversely, as the lever 35 movesdownwardly toward the nozzle 28, the valve 38 and stem 39 will beswivelled in a clockwise direction. In this manner the relationshipbetween the valve member and the port 30 with regard to alignment willbe the same throughout the entire range of movement of the lever 35.

The stream of air issuing from the port 30 will serve to center thevalve 38 but it may be desirable notwithstanding the natural centeringtendency of the air to provide additional means for centering such asthe magnet 44. The magnet 44 is positioned within the bore of the nozzle28. The magnet 44 is arranged with its poles being coaxial with theannular member 29. The magnet 44 is provided with cutaway sides 45 ascan be seen in FIG- URE 2 to permit the air to freely pass thereby andout the exhaust port 30. Obviously in this instance the valve member 38must be constructed of a magnetic material if it is to be acted upon bythe magnet 44. The eld of the magnet 44 will center the valve member 38with respect to its own center.

Thus as the apper 35 moves upwardly the field of the magnet 44 willswivel `the valve member 38 in a counterclockwise direction so as tomaintain it in alignment with the port 30. Conversely as the lever 35moves downwardiy the magnetic eld will move the valve member 33 in aclockwise direction so as to maintain an alignment with the port 3u.Although the valve 38 is rotated relative to the port 3S its naturalsymmetry eliminates any change in its valving characteristic.

Although certain specic forms and uses of the invention have beendisclosed in the description hereinbefore, it is to be understood thatthis is merely by way of example and is not to be construed as alimitation. It will be apparent to those skilled in the art that certainmodiiications may be made within the scope of the claims withoutdeparting from the spirit of the invention.

it is claimed:

il. A i'lapper nozzle arrangement comprising a valve member having astem portion, a spherical valve mounted on one end of said stem and aspherical swivel member on the other end of said stern opposite saidspherical valve, a movably mounted valve support member having anopening therein through which said stem portion of the valve extends, aspring biased member in engagement with the spherical lswivel member formaintaining the same in a seated position on said opening, and a valveseat member having a port therein, said valve member cooperating withsaid valve seat member in coaxial relationship with said port forcontrolling the ow therethrough.

2. A flapper nozzle arrangement comprising in combination a pivotallymounted apper member having an opening therein, a valve member having astem portion extending through said opening in said ilapper melmber andhaving spherical portions at each of its ends, one of said sphericalportions acting as a valve and the other of said spherical portionsacting as a connection to said tlapper member, a nozzle having a porttherein for exhaust to atmosphere, said valve member cooperating withsaid port for controlling the rate of exhaust, an adjustablespring-biased member for maintaining said other spherical portion inseating engagement on said opening and permitting swivel movement ofsaid valve member and said stem with respect to said apper member, saidvalve member and said stem being swiveled to maintain concentricity withsaid port as said apper member moves With respect to said nozzle.

3. A apper nozzle arrangement comprising a valve member having a stemportion, a spherical valve mounted on one end of said stem portion and aspherical swivel member at the other end of said stem opposite saidspherical valve, a movably mounted valve support member having anopening therein through which said stem portion extends, a spring biasedclip in engagement with said spherical swivel member for maintaining thesame in a seated position on said opening, .and a valve seat memberhaving a port therein, said valve member cooperating with said valveseat member in coaxial relationship with said port for controlling theflow therethrough, and magnetic means for swiveling said valve memberand said stem as said apper member moves with respect to said nozzle tomaintain concentricity of said valve member with said port.

4. A ilapper nozzle arrangement comprising in combination a pivotallymounted apper member having an opening therein, a valve member having astem portion extending through said opening and having sphericalportions at each of its ends, one of said spherical portions acting as avalve and the other of said spherical portions actinfy as a connectionto said apper member, a nozzle having a port therein for exhaust toatmosphere, said valve member cooperating with said port for controllingthe rate of exhaust, said valve member and said stem being swiveled tomaintain concentricity with said port as said llapper member moves withrespect to said nozzle, a magnet disposed within said nozzle swivelingsaid valve unember and said `stem portion as said apper member movesrelative to said nozzle to maintain concentricity between said valvemember and said port.

5. A apper nozzle arrangement comprising in combination a pivotallymounted apper member having an opening therein, a valve member having astem portion extending through said opening in said apper member andhaving spherical portions at each of its ends, one of said sphericalportions acting as a valve and the other of said spherical portionsacting yas a connection to said flapper member, a nozzle having a porttherein for exhaust to atmosphere, said valve member cooperating withsaid port for controlling the rate of exhaust, said valve member andsaid stem being swiveled to maintain concentricity with said port assaid ilapper member tmoves with respect to said nozzle, a magnetdisposed within said nozzle for swiveling said valve member and saidstem portion as said apper member moves relative to said nozzle tomaintain concentricity between said valve member and said port.

6. A flapper nozzle combination comprising a nozzle connected to apneumatic system, said nozzle exhausting air from said system wherebythe pressure within the system is proportional to the rate of exhaust, avalve member cooperating with said nozzle for controlling the rate ofexhaust, said valve member comprising a apper member having an openingtherein, a valve member having a stem portion extending through saidopening in said ilapper member and having spherical portions .at each ofits ends, one spherical portion acting as a valve and the otherspherical portion acting as a swivel connection to said apper member, anadjustable spring-biased member for maintaining said other sphericalportion in seating engagement on said opening and permitting the swivelmovement of said valve member and said stem, and means for swivelingsaid valve member and said stem Ias said flapper member moves withrespect to said nozzle so as to maintain concentricity between saidvalve member and said nozzle.

References Cited bythe Examiner UNITED STATES PATENTS 1,273,304 7/1918Yates 251-86 XR 1,832,341 11/1931 Williamson 251-86 2,669,247 2/1954Olah 137-84 3,237,633 3/1966 Sanville 137--82 ALAN COHAN, PrimaryExaminer.

1. A FLAPPER NOZZLE ARRANGEMENT COMPRISING A VALVE MEMBER HAVING A STEMPORTION, A SPHERICAL VALVE MOUNTED ON ONE END OF SAIS STEM AND ASPHERICAL SWIVEL MEMBER ON THE OTHER END OF SAID STEM OPPOSITE SAIDSPHERICAL VALVE, A MOVABLY MOUNTED VALVE SUPPORT MEMBER HAVING ANOPENING THEREIN THROUGH WHICH SAID STEM PORTION OF THE VALVE EXTENDS, ASPRING BIASED MEMBER IN ENGAGEMENT WITH THE SPHERICAL SWIVEL MEMBER FORMAINTAINING THE SAME IN A SEATED POSITION ON SAID OPENING, AND A VALVESEAT MEMBER HAVING A PORT THEREIN, SAID VALVE MEMBER COOPERATING WITHSAID VALVE SEAT MEMBER IN COAXIAL RELATIONSHIP WITH SAID PORT FORCONTROLLING THE FLOW THERETHROUGH.